1. Field of the Invention
The present invention relates to a curved surface signal pick-up device, wherein the graphic brushes are made from dividing a single located element, and the common portion and transferring portions are installed on the same radius, therefore, the rotation of a small angle can be detected, and thus the resolution is increase,
2. Description of the Prior Art
In the prior art single grid device, which is generally used in a mechanic mouse, as shown in FIG. 4, includes a conducted rotary disk, and a grid ring 71 is installed on the surface of the rotary disk, an insulating portion formed on the middle of the grid ring 711. The grid ring 71 is installed with a transferring portion 712 surrounding the axial center of the rotary disk and having a strip, and further installed three graphite brushes 81, 82 and 83. One ends of the three graphite brushes 81, 82 and 83 are connected with one circuit board 84. Another ends thereof are contacted with the transferring portion 712 and the insulating portion 711. Therefore, as the rotary disk is rotated, the graphite brushes 81, 82 and 83 will output different voltages according to the locations of the transferring portions 712. Namely, signals of 0 and 1 are outputted for transferring to the central processing unit of a computer.
However, in the conventional single grid encoder, the transferring portion 712 and insulating portion 711 are installed in different radii. Therefore, when a slight rotation is occurred, the graphite brushes 81, 82 and 83 have different moving distances so that the voltage variations are effected. Therefore, the resolution can not be improved. Moreover, since the lengths and positions of the graphite brushes are different, thus the fabrication process is complicated and the cost is increased.